Orifice for molten minerals



s-tent Office 3,521,663 ORIFICE FOR MOLTEN MINERALS Jack L. Brinkerhoif,Lawrence B. Horton, and Chao Hsiao, Pocatello, Idaho, assignors to FMCCorporation, New York, N.Y., a corporation of Delaware Filed Dec. 27,1966, Ser. No. 605,028

Int. Cl. F16k 49/00 US. Cl. 137-340 4 Claims ABSTRACT OF THE DISCLOSUREBACKGROUND OF THE INVENTION Field of the invention The invention coversa novel, adjustable, orifice means for controlling the flow of moltenslag to a fiberizing device at a uniform rate without plugging.

Description of the prior art Molten mineral slag, such as that obtainedfrom phosphate furnaces wherein phosphate ores are reduced to elementalphosphorus, can be converted to mineral wool fibers. This can beachieved by feeding the molten slag from the furnace or cupola. onto afiberizing apparatus, e.g. a fiberizing wheel, in a controlled, steadystream. A major difiiculty in the above process is keeping the moltenslag flowing at a steady rate from either an orifice or a pouring lip inthe furnace or cupola. Solidification of the molten slag in the pouringlip. or orifice and corrosion of the orifice by the slag commonly occurand make uniform slag flow difficult to maintain. As a result, there isa need for means which will permit the flow of molten slag at a steadyrate without the above problems.

SUMMARY OF THE INVENTION It has been found that a controlled, steadyflow of molten slag from a furnace onto a fiberizing device can beachieved by passing the slag through an orifice means which is definedby the ends of elongated, slideable metal elements radially disposedfrom said orifice and held in place by a support means; the elements canslide in their supports thereby increasing or decreasing the size of theorifice as desired. The size of the orifice can be maintained constantby moving the elongated metal elements towards the orifice as the endsof the metal elements are eroded away; the ends of the elongated,slideable metal elements that form the orifice thus can be constantlyrenewed.

BRIEF DESCRIPTION OF THE DRAWING In the drawing FIG. 1 illustratesaperspective 'view of the orifice means and the elements that form same,while FIG. 2 is a sectional view through one of the support meansillustrated in FIG. 1.

DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENTS In theprocessof making mineral wool fibers from molten mineral slag, the slag ismaintained in a molten state in a furnace and passed to a fiberizingapparatus to form the mineral wool fibers. One common example of afiberizing apparatus is a fiberizing wheel in which a controlled streamof molten slag is poured onto a rotating wheel and the molten slag isthrown tangentially from the wheel. The tangentially thrown particlesare then interrupted by a blast of a hot fluid gas, for example steam,and attenuated into fibers.

In such a process the quality of the mineral fibers produced is affectedby the uniformity and control of the flow of molten slag onto thefiberizing wheel. Normally, this flow can be accomplished by simplycontrolling the slag temperature and static head above an orifice.However, because of the high temperatures of the molten mineral slag theorifice is subject to corrosive attack and its cross-sectional areachanges with time, thereby changing the rate of flow and making flowcontrol more difficult. In the case of certain slags such as moltenphosphate slag obtained from the furnaces used to reduce phosphate oresto elemental phosphorus, corrosion of the orifice is so severe thatspecially designed orifices lined with molybdenum, tungsten or iridiumhave been utilized. However, these do not prevent corrosion, they merelyreduce the rate of corrosion. Therefore, orifices lined with thesemetals eventually corrode and present the same flow control problem asthe conventional metal orifices.

An additional difliculty in using molten mineral slag in forming mineralwool fibers is that mineral slag will only produce satisfactory fiberswhen the slag is within a relatively narrow temperature range. Thispresents a serious obstacle to producing acceptable mineral wool fibersbecause the slag which is removed from the furnace must contact thefiberizing apparatus within a very narrow temperature range. If there isa deviation in the flow rate or the time required for the molten slag toflow to the fiberizing apparatus, the mineral wool product which isobtained will not be acceptable. Thus, when making fibers from moltenmineral slag, control of the flow rate is even more critical than, forexample, when producing glass fibers since the temperature range forproducing acceptable glass fiber is much wider.

The invention will now be described with reference to the appendeddrawings. In the drawings:

FIG. 1 is a perspective view of the orifice means, and

FIG. 2 is a sectional view through one of the support means illustratedin FIG. 1.

In FIG. 1, 2 represents a frame to which is attached support means 4.The support means 4 are rigidly attached to the frame 2 about an openingin the center of frame 2. In addition there is also attached to frame 2guide means 6 which is located around and at the lip of the opening inframe 2. A plurality of metal elements 8 are held within support means 4in a slideable relationship so that the metal elements 8 can slide in aradial direction towards or away from the opening in frame 2 a portionof the elements 8 contact guide means 6 and projects over the opening inframe 2. The ends of element 8 that contact each other then define anorifice 10 which is smaller than the opening in frame 2. The size of theorifice can be regulated by increasing or decreasing the amount that themetal elements 8 project beyond guide means '6 into the opening of theframe 2.

The support means 4 as illustrated in FIG. 2 are made up of an innermetal holder 24 surrounded by an outer metal jacket 22 and containing ahollow section therein. Water, or other cooling liquid is circulatedbetween the inner and outer walls of the support means 4 to cool theelements 8 held within the support means 4. Water is introduced into onehollow support means 4 through water line 12 and then through the othersupport means ihrough lines 14, 1-6 and 18 and finally removed throughine 20.

In operation the orifice unit is fixed to the base of a furnace havingan opening therein so that the orifice covers an opening in the furnace(not shown). The slag is then permitted to pass through the furnaceopening, passed the orifice means, to the fiberizing apparatus.

The rate of flow of the molten slag through the orifice is regulated bythe size of the orifice. The orifice size, in turn, is controlled byadjusting elements 8. As the molten slag flows through the orifice 10there will be an unavoidable amount of corrosion erosion of the elements8. As this occurs the elements are inserted further in their supports 4so that the orifice 10 is maintained at a constant size. The cooling ofthe elements 8 has been found extremely effective in cutting down theamount of erosion. The cooling water circulated in the supports 4 coolsthe metal elements 8 to increase their resistance to corrosion by themolten slag, but they are not cooled sufficie-ntly so that molten slagsolidifies in the orifice.

In the above description and drawing of the preferred embodiment of theorifice, four support means, each containing a number of metal elements,have been illustrated. However, it should be realized that any number ofsupport means and metal elements can be used in the practice of thisinvention as long as they are positioned radially about the orifice.Further, the frame that holds supports 4 can be of any shape desired.

In the embodiment shown above, the metal elements 8 that make up theorifice have their ends reduced in thickness to obtain a thinner crosssection about the orifice. However, it is obvious that the ends of themetal elements can be uniform throughout, if desired, to obtain a crosssection about the orifice which is as thick as the metal elements 8.

The following example is given to illustrate the invention and is notdeemed to be limiting thereof.

Example 1 An orifice means, having the structure as set forth in thedrawing, was fixed onto an opening in the wall of a refractory containerinto which was flowed molten phosphate slag from an electric furnace. Anoverflow device on the container provided for a constant hydrostatichead of about 8 inches. The elongated elements used in the orifice meanswere inch by /2 inch by inches long and were constructed of (310)stainless steel. The orifice means was arranged with three elements perside so that the basic orifice opening was 2%. inches square.

The following test data was obtained:

Flow rate (lbs/hour) Observations Slag temperature, 2,620 F. Decreasedorifice size. Slag temperature, 2,610 F.

Slag temperature, 2,620 F. Slag temperature, 2,630 F.

End of test The above results indicate that a desired rate of flow ofthe slag can be selected and maintained with the present orifice meansand that the temperature of the molten slag remains substantiallyconstant during slag flow.

Pursuant to the requirements of the patent statutes, the principle ofthis invention has been explained and exemplified in a manner so that itcan be readily practiced by those skilled in the art, suchexemplification including what is considered to represent the bestembodiment of the invention. However, it should be clearly understoodthat, within the scope of the appended claims, the invention may bepracticed by those skilled in the art, and having the benefit of thisdisclosure otherwise than as specifically described and exemplifiedherein.

What is claimed is:

1. An adjustable orifice means for controlling the rate of fiow of amolten mineral comprising a frame having an opening therein, a pluralityof supports fixed to said frame disposed about said opening, saidsupports holding in slideable relationship a plurality of elongatedmetal elements positioned radially from said opening, a portion of eachof said metal elements extending over said opening in said frame anddefining an orifice within said opening by one end of each of said metalelements contacting adjacent elements, said elongated metal elementsbeing in substantially the same plane and independently slideablymounted whereby they can slide within said support members to maintainthe size and shape of the orifice formed at a predetermined, fixedposition by renewing the ends of said elongated metal elements as theyare eroded away.

2. The orifice means of claim 1 wherein said elongated metal elementsare cooled by cooling means that contain a cooling fluid in indirectcontact with said elements.

3. The orifice means of claim 1 wherein said supports have a hollowsection therein through which passes a cooling fluid to cool said metalelements located within said supports.

4. The orifice means of claim 1, wherein said molten mineral is mineralslag.

References Cited UNITED STATES PATENTS 497,903 5/1893 Woodward 251-212 X3,101,736 8/1963 Egger 25l212 X 3,329,396 7/1967 Heaton et a1. 251-2121,102,197 6/1914 Knox 137-340 2,875,725 3/1959 Lit et al. 1181252,994,624 8/1961 Lit et a1. 118-125 X 3,287,158 11/1966 Whitfield118-419 X JOHN P. MCINTOSH, Primary Examiner US. Cl. X.R. 251-212

